package com.barcode.camera;
import android.content.Context;
import android.hardware.Camera;
import android.os.AsyncTask;
import android.util.Log;
import java.util.ArrayList;
import java.util.Collection;
import com.barcode.executor.AsyncTaskExecInterface;
import com.barcode.executor.AsyncTaskExecManager;
/**
* 自动对焦管理
* @author 火蚁(http://my.oschina/LittleDY)
* @created 2014-03-14
*/
final class AutoFocusManager implements Camera.AutoFocusCallback {
private static final String TAG = AutoFocusManager.class.getSimpleName();
private static final long AUTO_FOCUS_INTERVAL_MS = 2000L;
private static final Collection<String> FOCUS_MODES_CALLING_AF;
static {
FOCUS_MODES_CALLING_AF = new ArrayList<String>(2);
FOCUS_MODES_CALLING_AF.add(Camera.Parameters.FOCUS_MODE_AUTO);
FOCUS_MODES_CALLING_AF.add(Camera.Parameters.FOCUS_MODE_MACRO);
}
private boolean active;
private final boolean useAutoFocus;
private final Camera camera;
private AutoFocusTask outstandingTask;
private final AsyncTaskExecInterface taskExec;
AutoFocusManager(Context context, Camera camera) {
this.camera = camera;
taskExec = new AsyncTaskExecManager().build();
String currentFocusMode = camera.getParameters().getFocusMode();
useAutoFocus = true && FOCUS_MODES_CALLING_AF.contains(currentFocusMode);
Log.i(TAG, "Current focus mode '" + currentFocusMode+ "'; use auto focus? " + useAutoFocus);
start();
}
@Override
public synchronized void onAutoFocus(boolean success, Camera theCamera) {
if (active) {
outstandingTask = new AutoFocusTask();
taskExec.execute(outstandingTask);
}
}
synchronized void start() {
if (useAutoFocus) {
active = true;
try {
camera.autoFocus(this);
} catch (RuntimeException re) {
// Have heard RuntimeException reported in Android 4.0.x+;
// continue?
Log.w(TAG, "Unexpected exception while focusing", re);
}
}
}
synchronized void stop() {
if (useAutoFocus) {
try {
camera.cancelAutoFocus();
} catch (RuntimeException re) {
Log.w(TAG, "Unexpected exception while cancelling focusing", re);
}
}
if (outstandingTask != null) {
outstandingTask.cancel(true);
outstandingTask = null;
}
active = false;
}
private final class AutoFocusTask extends AsyncTask<Object, Object, Object> {
@Override
protected Object doInBackground(Object... voids) {
try {
Thread.sleep(AUTO_FOCUS_INTERVAL_MS);
} catch (InterruptedException e) {
// continue
}
synchronized (AutoFocusManager.this) {
if (active) {
start();
}
}
return null;
}
}
}